71. Video transmission in TV broadcast is usually on
A.AM
B. PM
C. FM
D. SM

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72. For providing two or more voice circuits with the same carrier, it is necessary to use
A. pilot carrier system
B. ISB emission
C. lincompex
D. vestigial sideband transmission

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73. A duplexer isa device used to
A. feed more than one receiver from a single antenna
B. connect two transmitters to the same antenna
C. cannect a receiver and a transmitter to the same antenna
D.

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74. Polarisation of radio wave is determined
A. the directivity of the antenna
B. the direction of the magnetic flux lines w.r.t. the surface of the Earth.
C. the direction of the electric flux lines w.r.t. the surface of the Earth
D.

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75. The total bandwidth needed for an AM signal at 55.25 MHz with 0.5 video modulation is
A. 0.25 MHz
B. 0.5 MHz
C. 1 MHz
D. 10 MHz

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76. The RF section of a radio transmitter generally consists of
A. Master oscillator
B. Final power amplifier to feed antenna
C. Buffer stage
D. All of the above

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77.  In AM, the modulation envelope has a peak value double the unmodulated carrier level, when the modulation is
A.25%
B.33%
C.50%
D.100%

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